Is symptom outcome the whole story?-A multilevel meta-analysis of systemic therapy for adults including family system functioning

Objective: Systemic Therapy conceives mental health symptoms in the context of social systems. Previous meta-analyses on Systemic Therapy focused on symptoms. This meta-analysis aims to focus on family system functioning while including all types of outcomes. Method: We conducted a systematic literature research in multiple databases (PsycInfo, PubMed, Embase, Cochrane Central). We included RCT-studies on adults with psychiatric diagnoses, which compared Systemic Therapy with active psychosocial control. The literature research resulted in 171 coded effect sizes of 32 RCTs. We conducted a random-effects three-level meta-analysis. We categorized outcomes into symptoms of patients, family system functioning, further secondary outcomes of patients, and psychopathology of family members. Results: The results show a small significant overall effect size of g = .30 (CI: .15-.45, p < .001, k = 171, s = 32) for all outcomes. Systemic Therapy revealed small effect sizes with regard to family system functioning (g = .34, z = 3.51, p = .0004, k = 26, s = 12), symptoms (g = .30, z = 3.74, p = .0002, k = 73, s = 29), and further secondary outcomes (g = .32, z = 3.83, p = .0001, k = 63, s = 19). The effect sizes for psychopathology of family system members were reported rarely (k = 9, s = 6). Conclusion: This meta-analysis shows the potential relevance of investigating family system functioning as a primary outcome for Systemic Therapy.